Last week, social networking giant Facebook announced that it plans to create what it calls an "alternative financial system" based on a cryptocurrency called the Libra. The crypto will be backed by a basket of currencies to keep its value stable.

Pundits immediately pronounced that the Libra could represent the beginning of the end for traditional banking. But while Facebook's plunge into this space is the most ambitious effort by a Fortune 500 company to profit from the crypto market, the company hasn't exactly done a stellar job of protecting user data. That makes me skeptical of its ability to safeguard your money.

Last October, Facebook announced that hackers had compromised more than 30 million accounts by taking advantage of vulnerabilities that have now been patched. A month later, researchers uncovered a vulnerability in Facebook Messenger that hackers could use to reveal the identity of the people with whom you exchanged messages. And who can forget the seemingly innocent quizzes that were used to gain access to 50 million Facebook accounts in an effort to affect the outcome of the 2016 presidential election?

It's one thing to load photos of your cat doing stupid tricks onto your Facebook account. It's quite another to trust the company with your money. Although Facebook says that Libra's governance model will ensure "separation between social and financial data," I suspect Libra will appeal mainly to people who don't have bank accounts and have no practical way to open them. Facebook cited a figure of 1.7 billion adults in this category, with nearly half of them living in Bangladesh, China, India, Indonesia, Mexico, Nigeria, and Pakistan.

Still, the launch of the Libra is a proverbial shot across the bow for the banking industry. And it couldn't come too soon.

Our global financial system is built on the flawed foundation of a poorly understood concept called fractional reserve banking.

Five hundred years ago, if you owned valuables you didn't want to store at home, you could keep them in a secure warehouse. You gave the warehouse-keeper a sealed bag and received a receipt for it. You paid the warehouse-keeper a fee for keeping the bag safe. So long as the warehouse-keeper didn't run off with your valuables or let someone else steal them, your wealth was secure.

Not all depositors, however, insisted on receiving the same bag of valuables back from the warehouse-keeper. They were satisfied to receive back equivalent value. Depositors could now use the receipts warehouse-keepers issued as a medium of exchange.

Warehouse-keepers soon realized that not every receipt would likely be redeemed simultaneously. So they began lending out a fractional reserve of the stored valuables in exchange for interest payments. In this manner, warehouse-keepers evolved into interest-charging fractional-reserve banks.